Dental drill



(No Model.)

0. K. BRYANT.

- DENTAL DRILL.

No. 453,254. Patented June 2,1891.

.1 g 17 .6 [gm ifz'mewews Inventor:

7 UNITED STATES ATENT OFFICE.

CHARLES K. BRYANT, OF HARTFORD, CONNECTICUT.

DENTAL DRILL.

SPECIFICATION forming part of Letters Patent No. 453,254, dated June 2,1891. Application filed April 8, 1891. Serial No. 388,152. (No model.)

To all whom it may concern:

Be it known that I, CHARLES K. BRYANT, a citizen of the United States,residing at Hartford,in the countyof Hartford and State of Connecticut,have invented certain new and useful Improvements in Dental Drills, ofwhich the following is a specification.

This invention relates to dental drills, the object being to provide adrill-head especially adapted for safely and properly enlarging deviouscanals. To this end the invention consists in the improved drill-headhereinafter set forth.

In the drawings accompanying and forming a part of this specification,Figure l is an end view of the head of a dental drill embodyingmypresent invention. Fig. 2 is a side View of the drill shown in Fig. 1,as seen in the direction of the arrow m, Fig. 1. Fig. 3 is a sideelevation of the drill-head, as seen in the direction of the arrow.y,Fig. 1. Fig. 4. is a sectional view of the drill-head viewed in the samedirection as in Fig. 2, and illus trating the use of the instrument.Figs. 5 to 14:, inclusive, area series of sectional views in lines a toj, inclusive, Fig. 2, for more particularly illustrating the peculiarfeatures of the instrument. Fig. 15 is a diagrammatic view illustratingthe normal conformation of the drill-stem separately from the cuttinglips of the drill.

Similar characters designate like parts in all the figures.

The drill-head is formed on the point of the stem 10, which is providedwith the usual shank 12, whereby to hold the drill for using the same.The head of the drill is bounded by two cones, designated in Fig. 2 byr, s, and t, and r, s, and a, respectively. The first cone r s t is thecone of formation of the forward or advancing edges of the cutting-lipsof the drill. The other cone 1" s u is the cone of formation of therearward or following edges of the cutting-lips. These cones, it will beobserved, are set base to base, the cuttinglips being slightlyrounded atthe line (2 of the bases of the cones. The point of the leading cone 4.is preferablyrounded, as at 6, Figs. 2, 3, and at, so as to prevent saidcone from impinging into the side walls of a devious or flattened canal.

The forward cutting-edges 2 of the cuttinglips join the non-cuttingconical point 4 in substantial coincidence with the surface thereof, thecone of said forwardedges being a continuation of the cone of saidnon-cutting point. By this means the enlargement of a canal may becarried to the farthest point to which the non-cutting point can pass.Back of the point of its greatest diameter (indicated by the line d) thedrill-head decreases in diameter, the cutting-lips, however,being'continued to the rearward end of the drilLhead. The forward facesof the cuttinglips are conically formed throughout the length thereof.

For the purpose of increasing the cutting efficiency of thecutting-edges 2, and also for withdrawing the cuttings more freely, theforward surfaces or faces of the cutting-lips are concaved throughoutthe length thereof, and

the backward sides of said lips are convexly formed, so that incross-section, as shown in the several sectional views, Figs. 6 to 14,inclusive, the cutting-lips are hook-shaped. The concavely-formed faces8 of the spiral lips constitute spiral grooves for leading away theaccumulation of cuttings. The conveXly-formed backward faces 15 furnisha safe means for guiding the drill when it becomes necessary to reversethe rotation thereof for removing it from canals choked with adhesivecuttings; also for sharpening the drill by suitably grinding said convexsurfaces without distorting the cross-sectional outlines thereof.

The grooves 8 in the forward faces of the cutting-lips being not merelyundercut, but concavely formed, as set forth, retain, as against outwardmovement radially thereof, the cuttings while permitting the free passage thereof backward from the point of the drill-head, thus having adistinctive advantage over the old forms of undercut lips of dentaldrills. The advance cutting-edges of the drill-lips being coincidentwith the cone formation of the non-cutting drill-point enlarge the canalup to the extreme advanced position of said point.

As will be understood from Figs. 4 and 5, the stem 10 is, in a sense,continued through the drill-head to the non-cutting conical point 4,which point is, in fact, the termination of the drill-stem. Said stemfrom the base-linej of the drill-head is of a decreas- IOO ing diameteror thickness forwardly to the line 0 forward of a line (Z, whichcoincides with the bases of the aforesaid cones of formation. Thecutting-lips 2 2 are built or formed upon this tapered portion of thedrillstem, said lips being of increasing width (and also of decreasingthickness at theirjuncture with the stem) from the base-line j forwardto the said line (I. From the latter point the cutting-lips arereversely formed, having a decreasing width from the line (1 forward totheir juncture with the non-cutting drillpoint.

In using this instrument in the ordinary devious canals, as 18, Fig. at,the non-cutting point follows the said canal 18 of the root 20, andserves as a wedge to force sidewise the cutting end of the drill. Thisaction is illustrated in Fig. 4, showing the drill in sectional View andthe figure of rotation by dotted lines, this figure being bounded by twocones, as hereinbefore set forth. The forward cone,

terminating in the. non-cutting point, represents in this case thecutting-line of the instrument. The rearward cone conforms on one sidethereof to the inclination of the canal, and serves to bring out thecuttings, while itself not cutting, except in occasional instances.

While my improved dental drill is especially designed and constructedfor enlarging devious canals, it is equally eifective for enlargingstraight canals.

Having thus described my invention, I claim A drill-head having anon-cutting conical point and two spiral cutting-lips concavely grooved011 the forward side thereof, the cutting-edges of said lips conforming,as described, to two truncated cones set base to base and the forwardends of said edges joining the cone of said non-cutting pointinlinessubstantiallycoincident with the conical surface thereof, substantiallyas described.

CHARLES K. BRYANT.

Vitnesses:

HENRY L. RECKARD, H. MALLNER.

